In a sterile filling system such as an aseptic filling system, upon mounting a synthetic resin cap on a bottle (container) in which content such as a soft drink is filled, the cap is subject to sterilization and cleaning prior to supplying the cap to a capper. As cap sterilization-cleaning methods in the case, generally known are a method and a device for sterilizing and cleaning caps while transferring the caps in a chute based on their own weight (for instance, refer to Patent Document 1), and a method and a device for sterilizing and cleaning caps while transferring the caps in a turret or a drum-shaped star wheel (for instance, refer to Patent Documents 2 and 3).
With a chute-type sterilization-cleaning device, a cap transfer chute creates a transfer space with a plurality of rod-shaped guides disposed at least on the left, right, top and bottom in order to support the caps sideways to enable the cap to rotate, and the caps are transferred by passing through such transfer space. The caps transferred through the chute are sterilized and cleaned by injection of a sanitizer or aseptic water to the inner and outer surfaces of the caps from nozzles which are disposed at appropriate intervals on the left, right, top and bottom along the transfer passage. In many cases the sterilization-cleaning liquid is injected from the nozzles at an angle relative to the transfer direction so that the injected flow of the sterilization-cleaning liquid injected from the nozzles disposed along the chute is not obstruct the transfer of the caps.
Meanwhile, the present Applicant has previously devised and filed a patent application for a chute-type cap sterilization-cleaning device in which the chute transfer passage to be used in the sterilization-cleaning is configured in a rising slope so as to prevent deformation of the caps by relaxing the accumulated pressure working on the synthetic resin caps in the cap transfer chute, and enable the efficient sterilization-cleaning of the caps by reducing the influence of the warm water or aseptic water injected at the upstream side on the warm water or aseptic water on the downstream side (refer to Patent Document 4).